Yes you could find some spell to sumon a ghost-(heed my warning though") ( I have just started to be physically harmed because my friends sumoned one somehow and they can't stop it nor a priest I asked the priest said its a powerfull demon _ so all I can tell you is either don't do it or prepare for something harmfull)
Ok first of all you don't cast a spell to see ghosts, to see ghosts you have to have a gift, it's called being a medium and why would you want to see ghosts? Do you want to see ghosts or summon them? Because if you want to see them then you need to become a medium and if you want to summon them then you have to have a very good reason and summoning a ghost is very dangerous if you don't know what you are doing you will open your self up for some things that are not of this world so be careful.
You don't want to do that. Usually when you summon them, you get the worst ones, and you don't want to be harassed by them. It is a real pain to get rid of them. Hope this helps you out.